puzzles

Here are links to interactive online puzzles based on some of the recreational mathematics topics from this blog.

Logic PuzzlesThese are inspired by the puzzles of Raymond Smullyan. Generally, each type takes an example of a Smullyan puzzle and uses it as a template to generate hundreds more. Have fun. :)

The Forest of Forgetfulness: [blog], [puzzle], [source]
The Lion and the Unicorn are liars, but predictably so. Can Alice figure out what day it is based on what they are saying? Adapted from puzzles in Smullyan's What is the Name of this Book?

The Identical Twins: [blog], [puzzle], [source]
Tweedledee and Tweedledum are playing a logic game with Alice... can she deduce who is who? Adapted from puzzles in Smullyan's Alice in Puzzle-Land.

The Fickle Sentries: [blog], [puzzle], [source]
Two unreliable guards are standing at the entrance to a cave full of treasure - the treasure is yours if you can figure out what it is. A "new" puzzle based on those of Raymond Smullyan.

Knights and Knaves: [blog], [puzzle], [source]
You are on a very strange island: residence either always lie, or always tell the truth. Who can you trust? Adapted from puzzles in Smullyan's What is the Name of this Book? and other works.

Portia's Caskets: [blog], [puzzle], [source]
One casket contains Portia's portrait - there are clues printed on the caskets, but maybe these are lies?Adapted from puzzles in Smullyan's What is the Name of this Book?

The Case Files of Inspector Craig: [blog], [puzzle], [source]
A crime has been committed and Leslie Craig has some suspects in mind. Luckily these criminals follow very strict rules about whom they work with. Adapted from puzzles in Smullyan's The Lady or the Tiger.

Tiger or Treasure?: [blog], [puzzle], [source]
A guest must choose between two doors which may lead to treasure, or something less pleasant. Luckily there are inscriptions on the door to help... sometimes these are true, and sometimes they are false. Adapted from puzzles in Smullyan's The Lady or the Tiger.

The Isle of Dreams: [blog], [puzzle], [source]
On the Isle of Dreams, some residents think true thoughts when they are awake and false thoughts when they are asleep, while others think true thoughts when they are asleep and false thoughts when they are awake. Who is awake, who is asleep, and who is thinking correctly? Adapted from puzzles in Smullyan's The Lady or the Tiger.

Mathematical Chess Puzzles
Mathematical chess puzzles are not about the game, but about the rules of how the pieces can move and attack. The problem of movement leads to "tour" problems, and the problems of attack lead to puzzles like the "8 queens" puzzle.